Bilateral pulmonary hydatidosis associated with uncommon muscular localization.

Introduction: The lung is the second most commonly affected organ by hydatidosis, and the bilateral involvement is rare even in endemic regions.

Case Presentation: We report the case of a 27-year-old patient who presented with right basithoracic pain and cough evolving for three months. Thoracic CT scan revealed two homogeneous, rounded cystic formations enhancing after injection of the contrast media, located in the lateral basal segments of the lower lobe. An abdominal CT scan was performed to rule out a hepatic localization of the hydatid cyst, revealed a cystic formation of the left psoas muscle. The diagnosis of bilateral hydatid lung cyst associated with hydatid psoas muscle location was then made. The patient underwent a two-stage thoracic surgery. The second step involved partial cystectomy of the psoas muscle hydatid cyst via a left iliac incision and using an extraperitoneal approach. The postoperative course was uneventful.

Discussion: Management of bilateral pulmonary hydatid cyst is controversial. Some authors recommend operating bilateral cysts in two-stage surgery, with an interval of three to four weeks between procedures. The involvement of the psoas muscle is rare and is generally secondary to the rupture of splenic, hepatic or renal hydatid cysts. Generally, its diagnosis is delayed as the latter is most of the time asymptomatic.

Conclusion: Bilateral pulmonary hydatidosis associated with hydatid cyst of the psoas muscle is a rare entity. Radiological investigations and especially CT scan are the mainstay of diagnosis. Surgery remains to be the treatment modality of choice.